The catheter insertion apparatus for intravascular catheterization includes, as a rule, a catheter unit with a catheter tube and a catheter hub, a needle unit with a tubular needle and a needle hub as well as a hollow handle. Prior to use in the duty ready position, they are assembled so that the sharp distal point of the needle extends beyond the distal end of the catheter tube and the catheter tube extends beyond the distal end of the hollow handle. The user advances the catheter into the blood vessel and withdraws the needle unit leaving the catheter in the blood vessel. To prevent the user from being pricked, the withdrawn needle is transposed into the protection position avoiding the transmission of the infection by the blood contaminated needle. In this position, the needle unit is disposed inside the hollow handle and the needle sharp distal point is disposed in a security zone ruling out contact by the user with said sharp distal point. Thus, prior to use, the device has a relatively long length, which approximately is equal to the sum of the hollow handle length and the catheter unit length. In the protection position, the apparatus is substantially shorter because the needle unit is housed inside the hollow handle. In the development of modern catheter placement devices, there has been a tendency to reduce the device length in the transport and storage positions as well. This provides definite advantages such as the lower packaging and transportation cost. In said transport position, the device is compact because the catheter unit and the needle unit are positioned inside the hollow handle. Immediately before use, the apparatus is converted into the above duty ready position. Mentioned compact catheter insertion apparatus has to meet the following requirements:                Minimal length at the transportation and storage stages;        Easy conversion into the duty ready position;        Convenience of catheter placement;        Minimal number of unusual, non-customary manipulations;        Possibility of one handed trigger activation allowing for apparatus retraction into the protection position using the same hand which holds the apparatus;        Reliability of triggering off the means retracting the needle unit into the protection position;        Low manufacturing cost due to the easy of details fabrication and their assembly and also the decrease of the details number and material consumption.There are many catheterization devices having mentioned transport, duty ready, and protection positions.        
U.S. Pat. No. 4,988,339 discloses Retractable needle/syringe devices for blood collection, catheterization and medicinal injection procedures. The devices are comprised the needle unit in the form of a syringe and the catheter unit received in an oblong hollow handle with a retracting spring disposed in the hollow handle distal portion around the needle coaxially to it and the pusher of the needle unit, disposed axially at proximal handle face. The pusher is designed for manual transposition of the needle unit from the transport position into the duty ready position. The hollow handle is provided with slots for the transposition inside them a manual controlled drive of syringe piston and trigger member. The latter is designed for the control of needle unit retraction into the duty ready position. The disadvantage of this device is its great length caused by the needle unit pusher, which, in the transport position, protrudes in proximal direction and thereby increases the device length. Moreover, the necessity to provide the definite stroke of the syringe piston drive adds to the devices length and leads to the growth of material consumption. Another disadvantage is the absence of direct access to the catheter hub in the duty ready position (see FIG. 5 of U.S. Pat. No. 4,988,339). This impedes the control of the catheter by the user during catheter insertion into the patient's vein. Another disadvantage is the mutual disposition of the handle, the trigger member, and the pusher ruling out the possibility of the device control by the same hand, which holds the device. The device consists of many details including the proximal lid of the handle and the pin of the syringe piston drive, demanding separate fabrication and assembly. Other part of the details, such as the handle, syringe barrel, and piston, include many slots and notches, which significantly complicate their fabrication. As a result, the manufacturing cost of the device grows substantially. Another disadvantage is the possibility of the needle unit exit from the protection position as a result of the action onto accessible pusher and fixation means.
U.S. Pat. No. 5,480,385 discloses a self-retracting medical needle apparatus, which is comprised a needle unit and a catheter unit received in a hollow handle (container) in the transport position. The catheter unit is covered with a sheath having a tab on its distal end for the transposition of the catheter unit and the needle unit from the transport position into the duty ready position. The needle hub consists of two parts movable and immovable relatively the needle. They are connected with a frangible link. The part, immovable relative to the needle, is movable and hermetically sealed with respect to the interior of the hollow handle. The vacuum arises in the interior of the handle as a result of the needle hub transposition into the duty ready position. This vacuum creates a retracting force, which returns the needle unit into the protection position when the user ruptures the frangible link by a trigger. The movable part of the needle hub in the protection position retains at the hollow handle distal end. The disadvantage of the apparatus is its increased length in the transport position due to the protrusion of the sheath tab distally from the hollow handle distal end as well as increased length of the needle caused by applying the needle hub part movable relative to the needle. Another disadvantage is the unreliability of the retracting mechanism based on the vacuum force, which demands very tight sealing. Such sealing creates unstable friction between the needle hub and the hollow handle leading to jamming of the needle unit on the way to the protection position. The presence of this problem is corroborated with later U.S. Pat. No. 6,086,563 where an attempt was made to solve this problem. Another disadvantage is the increased outside diameter of the hollow handle caused by the necessity to provide free movement of the catheter hub inside the handle because the catheter hub is encircled with the sheath, having an inner thread, as well as a circular engagement recess on the hub movable part, which is located over the sheath. Said increased diameter impedes adjoining the catheter tightly to the patient's skin creating catheterization problems. Another disadvantage is the impossibility of converting the apparatus into the duty ready position by the same hand, which holds the apparatus. Moreover, said conversion is complicated by the necessity to remove the sheath after transposing the catheter unit into the duty ready position. The apparatus has a great number of the details including the sheath, proximal lid of the hollow handle and the means of needle hub sealing. There are very complex details—a needle hub consisting of two parts, a thread, recesses and unusual flash chamber. Along with the above mentioned increased length that adds to material consumption and fabrication complexity increasing the manufacturing cost of the apparatus.
U.S. Pat. No. 6,086,563 discloses Needle retraction mechanism with push start retraction, which includes: a needle unit with a cantilever resilient arm on the needle hub, a catheter unit, a needle cover with distally protruded tip for the transposition of the needle unit from the transport position into the duty ready position (called “extended position” in this patent). The needle unit, the catheter unit and the needle cover are housed in a hollow handle in the transport position. The hollow handle is provided with a trigger member (called “tab” in this patent) interacting with the cantilever arm of the needle hub. There also is a retracting mechanism (called “biasing mechanism” in this patent) founded on creating a vacuum force in the hollow handle as it was made in the previous U.S. Pat. No. 5,480,385. U.S. Pat. Nos. 5,480,385 and 6,086,53 have many of the same deficiencies. One disadvantage is the low reliability of the vacuum retracting mechanism in connection with the friction between the needle hub and the hollow handle. An attempt was made to solve this problem in U.S. Pat. No. 6,086,563 by specially configuring the interacting surfaces of the trigger member and the cantilevered arm. With this method, an axially directed constituent of force is created to overcome the friction force impeding the needle unit movement into the protection position. However, it should be taken into consideration that such a measure is effective only within reach of the trigger member, i. e. over the length of the short distal portion, and cannot overcome a jam in the middle and proximal portions of the hollow handle.
The apparatus according to U.S. Pat. No. 6,086,563 has increased length in the transport position because of the needle cover protruding distally beyond the hollow handle and the trigger member disposition at the distal end of the hollow handle beyond the needle. This apparatus also has a large number of details including the needle cover, a proximal lid of the hollow handle, a rubber cuff of the needle hub, a very complex needle hub with the cantilever arm, a recess for the needle cover engagement, a complicated flash chamber, and the holder of the rubber cuff. The increased length and fabrication complexity add to material consumption and, as a result, the manufacturing cost of the apparatus growths.
Thus, common disadvantages of the apparatuses with the transport position according to the prior art are:                Large length leading to increased material consumption and transportation expenses.        Inconvenience in operation due to the impossibility of controlling the device with one hand.        Low reliability of automatic conversion of the apparatus from the duty ready position into the protection position.        Relatively high manufacturing cost due to a large number of details, their complexity, and great material consumption.        Limitation on the application of catheter various types, in particular the catheters with hub having a side port and wings for attaching the catheter to patient's skin.        Possibility of the needle unit displacement from the protection position leading to personnel infection by blood contaminated needle.        